Filter plates of a filter press, having various structures are known in the art. A filter press shown in FIG. 35 is one of the known structures in which a filtrate drainage guide member 60b or a filtrate floor, for receiving a filtrate passing through a filter cloth and subsequently guiding it downwards, is formed in integration with a rectangular frame 60a and many recesses 60c, . . . , 60c are formed on both faces of the filtrate drainage guide member 60b, whereby the filtrate which has passed through the filter cloth flows down smoothly.
According to the above-described structure, however, the filtrate drainage guide member is integrally fixed to the frame, and further, these members are all rigid bodies, so that when there arises a large difference in pressure between one face and the other face of each filter plate during a filtration process, the filtrate drainage guide member is liable to deform against the frame, which may lead to breakage of the filtrate drainage guide member.
It is an object of the present invention to provide a filter press in which a filtrate drainage guide member is prevented from being broken when pressure applied to one face of a filter plate is much different from that applied to the other face. In accordance with this construction, the above-described disadvantage can be solved.